Vehicles include a fuel storage system for storing fuel, such as but not limited to gasoline, for an internal combustion engine. The fuel storage system includes a fuel tank for storing the fuel therein. Fuel tank headspace is occupied by fuel vapors, which are a mixture of air and hydrocarbons. As the tank is filled, the fuel vapors are forced out of the tank. In order to capture the expelled fuel vapors during fueling, the fuel tank is coupled to and in fluid communication with a canister. The fuel vapors expelled from the fuel tank during refueling operations flow into the canister. The canister includes a tightly packed bed of activated carbon particles that capture the fuel vapors, and prevents the fuel vapors from escaping into the atmosphere. The canister is coupled to the engine to supply the fuel vapors to the engine during operation. As such, when the engine is running, the engine draws the fuel vapors from the canister, and uses the fuel vapors for combustion.
The fuel vapors trapped within the fuel tank and the canister are subjected to diurnal, i.e., daily, expansion and contraction cycles caused by the daily increase and decrease in temperature. As the temperature rises, the pressure within the fuel tank and the canister increases. As the temperature cools, the pressure within the fuel tank and the canister decreases. Unless prevented, this diurnal expansion and contraction cycle may force the fuel vapors trapped within the canister into the atmosphere. This is particularly important for Extended Range Electric Vehicles and other hybrid vehicles that operate primarily on battery power, and may use an internal combustion engine only sparingly to charge the batteries or otherwise power the vehicle. In many circumstances, these hybrid vehicles may not operate, i.e., run, their internal combustion engine on a regular basis. As such, when the internal combustion engine of a hybrid vehicle is not operated over an extended period of time, the fuel vapors remain trapped within the canister. Continued exposure to additional fuel vapors from the fuel tank may cause the canister to become fully saturated. Accordingly, the fuel storage system must include an evaporate emission control system that minimizes and/or prevents the loss of fuel vapors.